基于多边形金纳米颗粒的非标记型可卡因适体传感器的研制

Label-free Cocaine Aptamer Biosensor Based on Polygonal Gold Nanoparticles

实验合成了多边形金纳米颗粒,通过壳聚糖(CHIT)将合成的多边形金纳米颗粒固定在玻碳电极表面,然后通过自组装技术将带巯基的捕获DNA探针固定在修饰有多边形金纳米颗粒的电极表面,利用杂交反应使可卡因适体与DNA捕获探针结合,制成非标记型可卡因适体传感器。以六氨合钌作为电化学指示剂,通过测量传感器与目标物可卡因结合前后电流变化情况对可卡因进行测定。考察了缓冲溶液的pH、可卡因培育时间、扫描速度等对测定的影响。结果表明,在pH为7.40时该传感器的检测范围为1.0×10-10～1.0×10-3 mol/L,检测限为3.0×10-11 mol/L。该传感器制作简单,响应好,抗干扰能力强。

Polygonal gold nanoparticles were synthesized and was immobilized on the surface of glassy carbon electrode through chitosan.The polygonal gold nanoparticles immobilized glassy carbon electrode was modified with complementary DNA through self-assembly.The electrode was incubated with cocaine aptamer for an hour to combine with the complementary DNA through hybridization for preparing label-free cocaine aptamer sensor.Hexaammine ruthenium（Ⅲ）chloride was used as the electrochemical indicator to determine cocaine by measuring current changes of the sensor before and after combined with the target cocaine.The effects of pH value,incubation time etc on the signal of the electrode have been investigated.The results show that linear range of the sensor was 1.0×10-10~1.0×10-3 mol/L with a detection limit of 3.0×10-11 mol/L.This electrochemical aptamer sensor is characterized with simplicity,low cost,good response,reproducibility and stability.